偶合物BSA-NASI在琼脂糖上预辐射接枝及其应用

PREIRRADIATION GRAFTING OF BSA NASI CONJUGATES ON AGAROSE AND ITS APPLICATION

将牛血清白蛋白（ＢＳＡ）与Ｎ－丙烯酰氧基丁二酰亚胺（ＮＡＳＩ）结合形成的偶合物接枝在预辐照过的琼脂糖上。并以此为柱填料对色氨酸的不同构型进行分离，经一次柱分离可从色氨酸中获得约２５％纯Ｌ型色氨酸。测定并计算了ＢＳＡ－ＮＡＳＩ偶合物与Ｌ－、Ｄ－、Ｄ，Ｌ－色氨酸分子的结合常数ｋＬ＝１．８×１０４Ｌ·ｍｏｌ－１、ｋＤ＝０．０、ｋＤ，Ｌ＝２．３×１０３Ｌ·ｍｏｌ－１。

BSA NASI conjugates are prepared at 37 ℃ for 2 h. The molar ratio of BSA and NASI in the conjugates is 1∶6. Preirradiation of Sepharose 4B is carried out at room temperature in air and grafting followed is performed below 37 ℃ for 5 h under bubbling nitrogen. The total dose is around 5 kGy. The combination constants k between L ,D , D,L tryptophans and BSA in conjugates are measured and calculated separately. They are: k L =1.8×10 4 L·mol -1 , k D =0.0 and k D,L =2.3×10 3 L·mol -1 . The k values are not affected by reaction temperature. The grafting copolymer as filling materials in column is used to separate D , L tryptophans. It shows that in a single separation about 25% of L tryptophan could be separated from the natural tryptophans. It indicates that this method may apply well to bioseparation with further improvements.